[8.x] What's new in 8.16 (backport #6077) (#6127)

* What's new in 8.16 (#6077)

* Whats new in 8.16

* Adds screenshots

* Update docs/whats-new.asciidoc

Co-authored-by: Nastasha Solomon <[email protected]>

* Comment out endpoint rules

* Add links

* comment out screenshot

* Add more links

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Co-authored-by: Nastasha Solomon <[email protected]>
(cherry picked from commit 411ac24)

# Conflicts:
#	docs/whats-new.asciidoc

* resolves conflict

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Co-authored-by: natasha-moore-elastic <[email protected]>
Co-authored-by: natasha-moore-elastic <[email protected]>

Author: mergify[bot]